Sexual-Health Reality Check: What You Really Need to Know About the HPV Vaccine

Imagine a vaccine that helps prevent cancer. Now imagine that it's going unused because of myths circulating online. That's what's happening with the HPV vaccine: A debunked article from 2009, which claims the shot doesn't work and that it has led to dozens of deaths, went viral again late last year, and University of Maryland researchers have found that 52 percent of the HPV-vaccine-related videos they examined on YouTube had a negative, disapproving tone. Now some experts fear these rumors are contributing to "horrifically low" vaccination rates for HPV—a sexually transmitted infection that affects nearly all adults and can cause genital warts and cancer. The Centers for Disease Control and Prevention estimates that this lifesaving vaccine could prevent 15,000 cases of HPV-related cancers each year, but a new study says that only 28 percent of women 18 to 26 report having started the three-dose series. Here are the facts.

Experts widely agree: The shots are safe.

As with any immunization, there can be side effects, but out of the 57 million doses given in the U.S., less than 2,000 cases of serious reactions have been documented—and some of those haven't been conclusively linked to the vaccine. "It's as safe as the flu shot," says Katharine O'Connell White, M.D., chief of the division of general obstetrics and gynecology at Baystate Medical Center in Springfield, Massachusetts. "The most common side effects are pain and redness at the injection site; 'more serious' symptoms include nausea and fainting. You have to balance the vaccine's risks against what's possible if you don't get it, which is cancer." Though some deaths have been reported, the CDC has investigated each case and found no evidence the vaccine was to blame.

And the shots are effective.

Gardasil, the most popular and widely available vaccine, offers nearly 100 percent protection against the 2 types of HPV that cause about 75 percent of reported cervical cancer cases. The vaccine also protects against other strains that cause genital warts.

You can still get the shot if you're already sexually active.

The vaccine is usually recommended for girls between ages 11 and 12 because it works best prior to HPV exposure. But some experts say adult women should also get it, even if they've already had HPV. "Your body could naturally fight off the infection, and then you can get HPV again," says Dr. White. "Getting vaccinated now may safeguard you against future infections." While the FDA has yet to officially recommend the vaccine to women over age 26, many doctors do prescribe it. "If you're not monogamous, you're probably going to see more penises!" says Dr. White.

One shot is better than none.

One study found that only 17 percent of women, on average, get all three doses of an HPV vaccine, which are supposed to be administered over a six-month period. Although that's better than nothing (National Cancer Institute research shows that one or two doses still help women develop higher anticancer antibody levels than unvaccinated women), a partial series may not be enough to keep you cancer-free, so it's best to follow up and get all the shots. "And if you still have questions about the HPV vaccine," says Dr. White, "hit up your gyno—not Google."